Citations are the primary tool to acknowledge others' prior work on a particular topic. They enable one to find key publications within a particular field, and are used also for research purposes – e.g. people working in Bibliometrics, Informetrics, and Scientometrics use them for analysing the complex relationships that exist within huge networks of citations of scholarly works. In addition, citation data are important for the assessment of the quality of research by means of metrics and indicators calculated from citation databases. However, the cruel reality is that citations have been locked up in close silos for years, and often they can only be accessed by paying significant subscription fees.

But the scenario is quickly changing. In the past years, several initiatives (I4OC, OpenCitations, WikiCite, Springer Nature SciGraph, LORC, etc.) have started to promote the availability of open citation data. In this talk I will introduce some of the main significative efforts in the area, focussing on the way Semantic Publishing technologies have been used and adopted for enabling a FAIR publication of open citation data.

To cite

Oxford dictionary: refer to (a passage, book, or author) as evidence for or justification of an argument or statement, especially in a scholarly work

Isaac Newton (1675): If I have seen further, it is by standing on the shoulders of giants

Citations are unanimously recognised as crucial for knitting together our scientific and cultural knowledge

References and citations

Everything is a reference

Semantic overload!

A citation is a conceptual directional link from a citing entity to a cited entity

Kinds of citations

Citations instantiated by the inclusion of a bibliographic reference (1)are different from those defined by an in-text reference pointer + citation context (2)

Generate a plain citation link

Generate a citation link with a specific citation function

Plain citations: current status

A citation index is an index of (plain) citations between publications

The most authoritative by institutions worldwide, namely Scopus and Web of Science, can be accessed only by paying significant access fees

Usually are more oriented towards human readability rather than machine readability and data re-use

What about machine-readable open citation data?

I4OC

The Initiative for Open Citations (I4OC, https://i4oc.org) is a collaboration between scholarly publishers, researchers, and other interested parties to promote the unrestricted availability of scholarly citation data

Goal: promote the availability of data on citations that are:

structured - available in common and machine-readable formats

separable - no need to access the source bibliographic products

open - freely accessible and reusable

Pathway to open citations

Publishers deposit their reference data with Crossref, but the default state for the data is closed (i.e. not accessible through the Crossref REST API)

However one email is enough to make the data open

Challenge: persuade a group of influential publishers to release their data

What happened: before I4OC launch (6 April 2017), 1% of publications in Crossref with open references

Publishers

49 scholarly publishers have opened their references, including the following major ones:

Learned societies - American Association for the Advancement of Science (AAAS), American Physical Society, American Society for Cell Biology, International Union of Crystallography, Proceedings of the National Academy of Sciences (PNAS), Royal Society of Chemistry, The Royal Society

Citation functions: what's up

When the citation links exist but are not described, the traveller through the city of scholarly publishing travels without specific directions, and will get lost in the maze of bridges that form the citation network